Various systems have been designed to accumulate media into collations. These systems have been for both folded and unfolded media which are accumulated into packets. The media can be individual sheets or a group of previously assembled sheets which are accumulated into packets often for further processing such as insertion into an envelope. Often, the accumulator systems are modules within such larger paper handling equipment such as folders and inserters. The accumulator systems provide a means within the paper handling equipment of assembling the media into a collation or packet prior to further processing such as systems that prepare bills or annual reports for mailing. Moreover, these accumulation systems often must process various types of media such as thin sheets, a group of previously assembled sheets and also stiff sheets which are transported through the accumulator system and are not accumulated into packets.
The accumulation systems have been for both forward and reverse accumulation. Forward accumulation is where the accumulation of media being stacked is in the opposite order in which they are fed into the accumulator. The first media becomes the bottom media in a stack of media or sheets and each subsequent media or sheet is laid on top of the preceding media or sheet. Thus, the forward accumulation of media results in the media being stacked in the opposite order in which they are fed into the accumulator. Reverse accumulation is where the accumulation of the media being stacked is in the order in which they are fed into the accumulator. The first media becomes the top media in a stack of media or sheets and each subsequent media or sheet is laid under the preceding media or sheet. Thus, the reverse accumulation of media results in the media being stacked in the order in which they are fed into the accumulator.
Accumulator systems also often involve various types of media which may be folded. Different types of folds may be implemented such as C-folds, Z-folds, half-folds, cross folds and the like. The specific fold employed depends on the specific application and the functionality of the specific equipment being employed as part of any larger system. For example, a specific application may require certain folded media to be accumulated into packets with an address bearing sheet at the top or the bottom of the collation or packet such that it may after collation with other media be inserted with a specific orientation into a windowed envelope. This is to have the address on the address bearing media be properly positioned behind the envelope window.
It is desirable to develop accumulator systems that have flexibility in their functionality, as well as ease in the mechanism set-up. This helps to increase the productivity of the equipment and also helps to facilitate user choices in running different applications that can involved various media types, folds types and media print order.
When handling stiff media such as stiff sheets as described above, it is advantageous to have a system that does not force the media to deform as it moves seriatim through the media accumulation system. Such a non-deforming mode has multiple advantages, such as the ability to process uniformly stiff media, media having non-uniform bending properties, for example, spine bound booklets, or media having non-uniform thickness.